They REALLY messed up the emulation on 8. They fucked the life bar colors, making it a piss dark yellow, and destroying the glossy effect it had, and they fucked up the sound, making shit like explosions obnoxiously loud, and speeding up the voices for the Robot Masters.
Also makes NO sense how 7, 8 and the Power Battles load instantly while the NES games take a while to load.
Also, all Anniversary collection really was is a shitty compilation of the 1-6 Complete Works re-releases but without a lot of the extra content. (like, helmet less Rock)
but to be fair, they DID give us a really fun navigation system for the menu, and the bonuses WERE pretty neat. You dont see much of that art even in R20 Official Complete Works. the remixed bonus tracks were pretty boss, and my only gripe was that there were system exclusive video bonuses. PS2 got a Mega Man episode, Xbox got an NT Warrior Episode I think, and gamecube got an actual interview with Inafune.